DE102022101474A1 - EXHAUST SENSOR ASSEMBLY - Google Patents

Abstract

An exhaust gas sensor assembly for a vehicle includes a sampling tube having a proximal end connectable to a housing and a distal end configured to be suspended from a cavity of the housing. The tube defines a hollow center, an inlet, an outlet, and an exhaust gas flow path extending from the inlet through the hollow center and to the outlet. An exhaust gas sensor is disposed in the hollow center at the proximal end and includes a sensing element disposed in the exhaust gas flow path. A flow guide is disposed in the hollow center between the inlet and the sensing element and is configured to redirect the flow path through a passage defined between the tube and the flow guide.

Description

TECHNICAL AREA

This disclosure relates to gas sensors, and more particularly to gas sensors used in a vehicle exhaust system.

BACKGROUND ART

Internal combustion engines produce exhaust gases during the combustion process. An exhaust system transports these exhaust gases from the engine into the atmosphere. Exhaust gases contain many different compounds, including nitrous oxide (NOx), oxygen, unburned fuel, carbon monoxide and carbon dioxide. Modern computer controlled engines monitor these connections with sensors to facilitate engine operation.

EXECUTIVE SUMMARY

According to one embodiment, an exhaust gas sensor assembly for a vehicle includes a sampling tube having a proximal end connectable to a housing and a distal end configured to be suspended from a cavity of the housing. The tube defines a hollow center, an inlet, an outlet, and an exhaust gas flow path extending from the inlet through the hollow center and to the outlet. An exhaust gas sensor is disposed in the hollow center at the proximal end and includes a sensing element disposed in the exhaust gas flow path. A flow guide is disposed in the hollow center between the inlet and the sensing element and is configured to redirect the flow path through a passage defined between the tube and the flow guide.

According to another embodiment, a sensor assembly for a vehicle includes a sensor and a sampling tube surrounding the sensor. The tube defines an inlet, an outlet, and a hollow center configured to direct a gas from the inlet past the sensor and to the outlet. The tube includes a flow guide that partially blocks the hollow center and cooperates with the tube to define a gap.

According to yet another embodiment, a vehicle exhaust system includes an exhaust pipe having a sidewall and a sensor assembly attached to the sidewall. The sensor assembly includes a sampling tube protruding from the sidewall toward a center of the exhaust pipe. The sampling tube defines a hollow center, an inlet to the hollow center, and an outlet from the hollow center. The sensor assembly further includes a sensor that extends through the sidewall to be received in the hollow center. A flow guide is located in the hollow center and cooperates with the tube to define a passageway.

character list

• 1 Figure 12 illustrates a portion of an exhaust system having a gas sensor for taking a sample of the exhaust gases.
• 2 Figure 12 illustrates a schematic side view of a gas sensor assembly.
• 3 Figure 12 illustrates another schematic side view of a gas sensor assembly.

DETAILED DESCRIPTION

This document describes embodiments of the present disclosure. However, it should be understood that the disclosed embodiments are merely examples and that other embodiments may take various and alternative forms. The figures are not necessarily to scale; some features may be enlarged or reduced to show details of particular components. Accordingly, the specific structural and functional details disclosed herein are not to be construed as limiting, but merely as a representative basis for teaching one skilled in the art to utilize the present invention in a variety of ways. It will be appreciated by those of ordinary skill in the art that various features illustrated and described with reference to any one of the figures may be combined with features illustrated in one or more other figures to produce embodiments that are not expressly illustrated or are described. The combinations of features shown provide representative embodiments for typical applications. However, various combinations and modifications of features consistent with the teachings of this disclosure might be desirable for particular applications or implementations.

With reference to 1 A vehicle exhaust system 20 is configured to direct an exhaust flow 22 from the engine to the atmosphere. The exhaust system 20 may include one or more sections of exhaust pipe, catalyst(s), resonator(s), muffler(s), aftertreatment components, and the like. In the illustrated embodiment, a gas sensor assembly 28 is at an extended Housing 30 of system 20 attached. The housing 30 may be connected to upstream and downstream exhaust pipes 24 and 26 . The housing 30 may be part of the catalytic converter, an exhaust pipe, or other structure. In the illustrated embodiment, the housing 30 is the can of the catalytic converter.

The gas sensor assembly 28 may be attached to a side wall 32 of the housing 30 . The gas sensor assembly 28 extends into an open cavity 34 of the housing 30 to be positioned within the exhaust flow 22 . The sensor assembly 28 includes an exhaust gas sensor 36 configured to read a concentration of one or more compounds of the exhaust stream 22 . For example, the sensor 36 may be configured to measure concentrations of nitrous oxide, oxygen, another gas, or combinations thereof.

As will be described in more detail below, the sensor assembly 28 includes a sampling tube 40 extending inwardly from the sidewall 32 toward a longitudinal centerline 42 of the housing 32. The sampling tube 40 may be radially disposed, as shown in the illustrated embodiment, or may be in a be appropriate angle. The sampling tube 40 is configured to draw the gas stream 22 located near the mid-section of the cavity 34 to the sensor 36 located near the side wall 32 . The sampling tube 40 improves accuracy by directing more of the exhaust flow 22 to the sensor 36 than would otherwise be the case without the sampling tube 40 . Because the sensor 36 is located on the sidewall 32, it can accommodate less flow, particularly when the housing 30 has a larger diameter. In addition, it is possible that the exhaust gas flow 22 is inhomogeneous and has different gas concentrations along its cross section. If the sensor 36 only senses the outer portions of the exhaust stream 22, it is possible that inaccurate readings will be produced. The sampling tube 40 includes a plurality of inlets 44 located at different radial positions of the tube. The inlets 44 are located on an upstream side 48 of the tube 40 . The sampling tube 40 is hollow and directs the airflow entering the inlets 41 to the sensor 36. An outlet 46, located adjacent to the sensor 36, allows the exhaust gases to exit the sampling tube 40. A sensing element of the sensor 36 measures the concentrations of the gases as they flow past. The outlet 46 is located on a downstream side 50 of the tube 40 .

While the hollow center 52 of the sampling tube is capable of channeling exhaust gases 22 to the sensor 36, testing has shown that this alone may be insufficient in certain situations. For example, it is possible for the gas flow within sampling tube 40 to largely bypass sensor 36, e.g. B. when a majority of the flow is along the downstream inner wall of the pipe 40. To solve this problem, a flow guide 54 is added to force the gas flow over the sensor 36. The flow guide 54 may be a plate or wall that covers a portion of the hollow center and forces the gas flow up the upstream inner wall of the tube 40 . This can create a perpendicular flow across the sensor 36 as the gas stream flows to the outlet hole 46 .

With reference to 2 The sensor 36 can be of any construction or configuration known in the art. At a high level, the sensor 36 may include a shell 60 and a sensing element 62 disposed within the shell. The shell 60 defines a plurality of inlet openings 64, e.g. B. Holes. The shell 60 may be cylindrical and the holes 64 may be provided circumferentially around the cylinder. The shell 60 may also define a plurality of outlet openings 66, e.g. B. holes, which can also be arranged in the circumferential direction. During operation, a portion of the gas stream 68 flows through the inlet ports 64, over the sensing element 62, and out the outlet ports 66. The sensing element 62 is configured to sense concentrations of one or more gases as the stream 68 flows past. For example, sensing element 62 may be configured to sense nitrous oxide, oxygen, or the like. The sensor can be mounted using a mounting boss configuration that can be integrated into the sampling tube.

Referring to the 2 and 3 sampling tube 40 includes a proximal end 80 , a distal end 82 , a longitudinal centerline 84 , and a centerline 86 perpendicular to longitudinal centerline 84 . The sampling tube 40 includes a sidewall 88, which may be a circular cylinder, extending from the proximal end 80 to the distal end 82. FIG. The distal end 82 may be generally closed with a drain hole. An end cap may be attached to sidewall 88 to form distal end 82 . Sidewall 88 includes an outer surface 90 and an inner surface 92. Sidewall 88 also includes an upstream side 94 facing gas flow 22 and a downstream side 96. Inlets 44 are located which is on the upstream side 96 to receive the incoming gas stream 22 into the hollow center 52. Inlets 44 are one or more openings, such as holes, that extend through sidewall 88 from outer surface 90 to inner surface 92 . The holes can be circular, oval or any other shape. The inlets 44 may be arranged in a linear array along the axial (longitudinal) direction 100 of the sampling tube 40 . The inlets 44 are more concentrated near the distal end 82 to accommodate the portion of the gas flow 22 near the centerline 42 of the exhaust system. Outlet 46 is on downstream side 96 and generally near distal end 80. Unlike inlets 44, sampling tube 40 may include only a single outlet 46. However, in other embodiments multiple outlets may be provided. Outlet 46 may be a hole that extends through sidewall 88 from outer surface 90 to inner surface 92 . Hole 46 may be circular, oval, or any other shape.

The sensor 36 is positioned within the hollow center 52 of the sampling tube 40 . For example, the sensor 36 can be received through the open distal end 80 of the sampling tube 40 . This suspends the sensing element 62 in the hollow center 52 . The outlet 46 is positioned to be generally adjacent to the sensing element 62 of the sensor 36 to provide optimal readings. The sampling tube 40 and sensor 36 may be attached to a head 104 of the sensor assembly 28 . The head 104 may be configured to attach to the housing 32 or other mount, e.g. B. a tube sidewall to be appropriate. The sensor assembly 28 may include threads or other means for attachment to the exhaust system 20 .

To improve gas flow through the sensing element 62, a flow guide 54 is provided within the sampling tube 40. FIG. The flow guide 54 blocks a substantial portion of the hollow center 52 and forces the gas flow to flow through a passage 106 located along the inner surface 92 of the upstream side 94 . The flow guide 54 may be a separate component attached to the sampling tube 40 or may be an integrally formed portion of the sampling tube 40 . In the illustrated embodiment, the flow guide 54 is a plate that is attached to the sampling tube 40, such as by welding or other means. The plate may be orthogonal to the axial direction 100. The plate may also be angled within the sampling tube 40 in other embodiments.

Flow guide 54 includes a first planar surface 110 extending across a substantial portion of the hollow center, thereby forcing gas flow through restricted passage 106 . The flow guide 54 can block at least 50% of the hollow center. In other embodiments, the flow guide 54 blocks at least 60%, 70%, 80%, or 90% of the hollow center. The planar surface 110 may be radially oriented (direction 102) with respect to the axial centerline 84 of the tube 40 (as shown) or may be inclined. The flow guide 54 may also include a second surface 112 which may also be a planar surface parallel to the first planar surface 110 . Alternatively, the second surface 112 may have a different shape or orientation than the planar surface 110 . Flow guide 54 may be shaped generally as a planar disc with a portion removed to create passage 106 . That is, the flow guide 54 may have a peripheral edge 114 located on the inner surface 92 of the sampling tube 40 on the downstream side and surrounding area and a straight edge 116 spaced from the inner surface 92 on the upstream side and the surrounding area to create a gap 105 that forms the passage 106. Gap 105 may be diametrically opposite outlet 46 . The size of the gap 105 can be tuned to provide the desired gas flow to the sensor 36 .

Flow guide 54 is positioned axially between uppermost inlet 44 and outlet 46 . This may position flow guide 54 between midpoint 86 and distal end 80 . In the illustrated embodiment, the flow guide 54 is closer to the distal end 80 than the midpoint 86. However, this is not required and depends on the flow characteristics of the assembly 28.

It should be understood that the flow guide 54 described above is merely an example and that the flow guide 54 can be any shape, size or shape capable of forming a restricted passage to direct the flow near the upstream side of the to guide sensors.

While exemplary embodiments are described above, these embodiments are not intended to describe all possible forms that are encompassed by the claims. Rather, the terms used in the description are descriptive terms cke as limiting terms, and it is understood that various changes can be made without departing from the spirit and scope of the disclosure. As described above, the features of various embodiments can be combined to form further embodiments of the invention that may not be expressly described or illustrated. Although various embodiments may have been described as advantageous or preferred over other embodiments or implementations of the prior art in terms of one or more desired characteristics, those of ordinary skill in the art will recognize that one or more features or characteristics may be compromised to achieve the desired Achieving overall system attributes that depend on the specific application and implementation. These attributes may include, but are not limited to: cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, maintainability, weight, manufacturability, ease of assembly, etc. Thus, there are embodiments that are less desirable in terms of one or more properties other embodiments or implementations described in the prior art are not outside the scope of the disclosure and may be desirable for particular applications.

According to the present invention, there is provided an exhaust gas sensor assembly for a vehicle, comprising: a sampling tube having a proximal end connectable to a housing and a distal end configured to be suspended from a cavity of the housing includes wherein the tube defines a hollow center, an inlet, an outlet, and an exhaust gas flow path extending from the inlet through the hollow center and to the outlet; an exhaust gas sensor disposed in the hollow center at the proximal end and including a sensing element disposed in the exhaust gas flow path; and a flow guide disposed at the hollow center between the inlet and the sensing element and configured to redirect the flow path through a passage defined between the tube and the flow guide.

According to one embodiment, the passage has a smaller cross-sectional area than the hollow center.

According to one embodiment, the flow guide includes a planar surface that is radially oriented relative to an axial centerline of the tube.

According to one embodiment, the tube includes a cylindrical sidewall extending between the proximal and distal ends, the sidewall having an upstream side defining the inlet and a downstream side defining the outlet.

According to one embodiment, the flow guide is located on the downstream side and spaced from the upstream side to form the passage therebetween.

In one embodiment, the flow guide blocks at least 50 percent of the hollow center.

According to one embodiment, the flow guide is a plate.

According to one embodiment, the plate includes a first peripheral edge disposed adjacent the tube and a second peripheral edge spaced from the tube to define the passage.

According to one embodiment, the exhaust gas sensor is configured to measure nitrous oxide.

According to one embodiment, the inlet is a plurality of inlets.

According to the present invention, there is provided a sensor assembly for a vehicle, comprising: a sensor; and a sampling tube surrounding the sensor, the tube defining an inlet, an outlet, and a hollow center configured to direct a gas from the inlet, past the sensor and to the outlet, the tube including a flow guide partially blocking the hollow center and cooperating with the tube to define a gap.

According to one embodiment, the flow guide includes a planar surface that is orthogonal to a longitudinal axis of the tube.

According to one embodiment, the flow guide is a plate oriented orthogonally to a longitudinal axis of the tube.

According to one embodiment, the gap is diametrically opposite the outlet.

According to one embodiment, the tube includes a proximal end connected to the sensor, a distal end, and a longitudinal end center point, with the inlet being between the distal end and the midpoint and the flow restrictor being between the midpoint and the proximal end.

According to one embodiment, the sensor is configured to measure nitrous oxide.

According to the present invention, there is provided a vehicle exhaust system, comprising: an exhaust duct having a sidewall; and a sensor assembly attached to the sidewall and including: a sampling tube protruding from the sidewall toward a center of the exhaust pipe and defining a hollow center, an inlet to the hollow center, and an outlet from the hollow center, wherein a sensor extends through the sidewall to be received in the hollow center; and a flow guide is disposed in the hollow center and cooperates with the tube to define a passage.

According to one embodiment, the gap is diametrically opposite the outlet.

According to one embodiment, the passage has a smaller cross-sectional area than the hollow center.

According to one embodiment, the flow guide is a plate oriented orthogonally to a longitudinal axis of the tube and a portion of the plate is spaced from an inner wall of the tube to define the passage.

Claims (15)

An exhaust gas sensor assembly for a vehicle, comprising: a sampling tube including a proximal end connectable to a housing and a distal end configured to be suspended from a lumen of the housing, the tube having a hollow center, an inlet, an outlet and a defining an exhaust gas flow path extending from the inlet through the hollow center and to the outlet; an exhaust gas sensor disposed in the hollow center at the proximal end and including a sensing element disposed in the exhaust gas flow path; and a flow guide disposed in the hollow center between the inlet and the sensing element and configured to redirect the flow path through a passage defined between the tube and the flow guide. sensor assembly claim 1 , wherein the passage has a smaller cross-sectional area than the hollow center. sensor assembly claim 1 wherein the flow guide includes a planar surface radially aligned relative to an axial centerline of the tube. sensor assembly claim 1 wherein the tube includes a cylindrical sidewall extending between the proximal and distal ends, the sidewall having an upstream side defining the inlet and a downstream side defining the outlet. sensor assembly claim 4 wherein the flow guide is located on the downstream side and is spaced from the upstream side to form the passage therebetween. sensor assembly claim 1 , with the flow guide blocking at least 50 percent of the hollow center. sensor assembly claim 1 , where the flow guide is a plate. sensor assembly claim 7 wherein the plate includes a first peripheral edge disposed adjacent the tube and a second peripheral edge spaced from the tube to define the passage. sensor assembly claim 1 , wherein the exhaust gas sensor is configured to measure nitrous oxide. sensor assembly claim 1 , wherein the inlet is a plurality of inlets. Sensor assembly for a vehicle, comprising: a sensor; and a sampling tube surrounding the sensor, the tube defining an inlet, an outlet and a hollow center configured to direct a gas from the inlet past the sensor and to the outlet, the tube including a flow guide, partially blocking the hollow center and cooperating with the tube to define a gap. sensor assembly claim 11 wherein the flow guide includes a planar surface orthogonal to a longitudinal axis of the tube. sensor assembly claim 11 wherein the flow guide is a plate oriented orthogonally to the longitudinal axis of the tube. sensor assembly claim 11 , where the gap is diametrically opposite the outlet. sensor assembly claim 11 wherein the tube includes a proximal end connected to the sensor, a distal end, and a longitudinal midpoint, the inlet being between the distal end and the midpoint, and the flow restrictor being between the midpoint and the proximal end.

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